1. Field of the Invention
The present invention relates to an image reading apparatus, an image forming apparatus, and an image reading method.
2. Description of the Related Art
Conventionally, the image reading apparatus has been adapted to convert, into a voltage, charges accumulated by allowing light-receiving elements such as a plurality of photodiodes to receive light and then sequentially convert the voltage from analog to digital, whereby a plurality of pieces of pixel data are sequentially outputted and the pixel data is collected line by line in the main-scanning direction in order to read an image. In short, in order to obtain one line of image data, all the pixel data had to be sequentially outputted pixel by pixel in the main-scanning direction.
On the other hand, in Japanese Patent Application Laid-Open No. 2012-78141, there is disclosed a displacement sensor which has an additional function for changing the start position for reading an image in order to change the range of reading the image.
However, the above-mentioned conventional art has a problem that required pixels can not be read with efficiency.
In view of the above described problems, there is need to provide an image reading apparatus, an image forming apparatus, and an image reading method which can read required pixels with efficiency.